Hydrogenation of aromatics

ABSTRACT

Aromatic hydrocarbons are hydrogenated in the presence of hydrogen and a catalyst composite comprising at least two hydrogenating agents and an alumina support having a controlled bayerite concentration, average pore radius, and pore volume distribution and further having been calcined at a temperature in the range of 800° - 1600° F. (427° - 871° C.) prior to impregnation of the hydrogenating agent.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 326,692, filed Jan. 26, 1973,now U.S. Pat. No. 3,876,680, which application is a continuation-in-partof application Ser. No. 272,018, filed July 14, 1972, and now abandoned.

BACKGROUND OF THE INVENTION

The hydrogenation of aromatic hydrocarbons is well-known in the art. Itis also known to use catalyst compositions in such hydrogenationprocesses comprising supported hydrogenating components consisting of atleast one member of Group VI-B and at least one member of the Group VIIImetals in a form capable of promoting hydrogenation reactions.Especially effective catalysts are those comprising nickel and tungsten.Other catalysts found to be effective include those containing nickel,cobalt and molybdenum, nickel and molybdenum and cobalt and molybdenum.The hydrogenating components of such catalysts can be employed insulfided or unsulfided form.

Although the hydrogenating components indicated above can be employed inany proportions with each other, especially effective catalysts arethose in which the hydrogenating components are those in the groupconsisting of oxides and sulfides comprising (a) a combination of 5 - 25percent by weight of a Group VI-B metal and (b) 5 - 20 percent by weightof a Group VIII metal. The hydrogenating components can be compositedwith a porous alumina support. The alumina support is normally shaped inthe form of granules, pellets or balls, prior to compositing thehydrogenating metals therewith. The catalyst composite, however can bein other forms such as a powder which is employed for conventional fluidtype operations.

Conventionally, in the preparation of the prior art catalyst compositesthe hydrogenation component such as tungsten is deposited on the supportfrom an aqueous solution of the salt. After filtering and drying, theimpregnate is calcined to convert it into the oxide. Th carrier is thentreated with an aqueous solution of the iron group metal salt such asnickel, followed by calcining. If a second iron group metal is employed,the second iron group metal can also be deposited in a like manner.Nitrates or acetates of the iron group metals are normally utilizedalthough any water soluble salt which leaves no harmful residue can beemployed.

If desired, the iron group metals and the Group VI-B metal can bedeposited simultaneously but are preferably deposited in sequence withintervening calcining. Simultaneous impregnation of the iron groupmetals has been found to be satisfactory.

Calcining of the catalyst composite can be conducted by heating in airto a temperature of 800° to 1600°F. (427°-871°C.). When a sulfidedcatalyst is desired, the catalyst prepared as described above can betreated in a known manner with hydrogen sulfide or preferably a mixtureof hydrogen and hydrogen sulfide. Typically, the catalyst composite canbe presulfided after calcination, or calcination and reduction, prior tocontact with the charge stock, by contacting with a sulfiding mixture ofhydrogen and hydrogen sulfide. Normally, the sulfiding is conducted at atemperature in the range of 500° to 650°F. (260° to 343°C.) atatmospheric or elevated pressures. Presulfiding can be convenientlyeffected at the beginning of an onstream period at the same conditionsto be employed at the start of the hydrogenation process. The exactproportions of hydrogen and hydrogen sulfide are not critical andmixtures containing low or high portions of hydrogen sulfide can beused. Relatively low proportions are preferred for economical reasons.Elemental sulfur or sulfur compounds, such as mercaptans, can be used inlieu of hydrogen sulfide.

Although the above-identified catalyst compositions are useful in thehydrogenation of petroleum aromatic hydrocarbons, it is desirable toimprove the efficiency of such aromatic hydrogenation processes at agiven operating temperature and, in some instances, obtain highhydrogenation process conversions at lower operating temperatures.

Accordingly, an object of this invention is to provide an impovedaromatic hydrogenation process.

Another object of the invention is to provide a novel catalystcomposition for the hydrogenation of aromatic hydrocarbons.

Yet another object of the invention is to provide a process for thepreparation of an improved hydrogenation catalyst composition.

Other objects, advantages and features of the invention will be readilyapparent to those skilled in the art from the following description andappended claims.

SUMMARY OF THE INVENTION

An improved aromatic hydrocarbon hydrogenation process is obtained byemploying in the hydrogenation process a catalyst composition comprisingat least two hydrogenating agents deposited on a calcined aluminasupport and wherein at least 40 percent of the volume of pores of thecatalyst composite will be in pores having a radius in the range of 50 -300 A units, the average pore radius of the catalyst composite being atleast 40 A units as determined by nitrogen adsorption, the surface areaof the catalyst composite being at least 150 square meters per gram, andthe pore volume of the catalyst composite being at least 0.45 cubiccentimeter per gram. Preferably, the catalyst composite employed in thehydrogenation process will have a pore volume of at least 0.60 cc/g asdetermined by the difference between mercury and helium densities by theprocedure described in "Introduction to Principles of HeterogenousCatalysis" by J. M. Thomas and W. J. Thomas, Academic Press, 1967, pages195 - 196, hereinafter referred to as the mercury test method. Further,the preferred catalyst composite shall have a maximum compacted densityof 0.75 gram per cc.

DESCRIPTION OF THE INVENTION

As described in the parent application, an improved hydrogenationprocess is obtained by employing a catalyst composition comprising atleast one hydrogenating component deposited on a calcined aluminasupport and wherein at least 40 percent of the volume of pores will bein pores having a radius in the range of 50 to 300 A units, the averagepore radius of the catalyst being in the range of 40 to 80 A units, thesurface area of the catalyst composite being at least 150 square metersper gram, and the pore volume of the catalyst being at least 0.4 cubiccentimeter per gram. It has been discovered that this catalystcomposition containing a metal from Group VI-B and a metal from GroupVIII is effective as an aromatic hydrocarbon hydrogenation catalyst.

The novel catalyst is applicable to the hydrogenation of aromatichydrocarbons and finds particular application in the hydrogenation ofaromatic hydrocarbons obtained from petroleum fractions. Examples ofpetroleum fraction feeds particularly suitable in the process of thisinvention are kerosene, furnace oils, gas oils and cycle oils obtainedby conventional catalytic cracking processes. The

The improved hydrogenation catalysts of this invention can be preparedby depositing a Group VI-B metal component and a Group VIII metalcomponent on a calcined alumina support so as to obtain a catalystcomposite having a relatively large average pore radius of at least 40 Aunits. Additionally, at least 40 percent of the pore volume of thecatalyst composite, as determined by the nitrogen adsorption methoddescribed by E. V. Ballou, O. K. Dollen, in Analytical Chemistry, Volume32, page 502, 1960, is contained in pores having a radius in the rangeof 50 - 300 A units. Th pore volume distribution figures employed inthis application are all obtained by the nitrogen adsorption method. Thepore volume as determined by nitrogen adsorption of the catalystcomposite should be at least 0.45 cc per gram and the surface area ofthe catalyst composite should be at least 150 square meters per gram.The pore radius as employed in this application is determined bymultiplying the pore volume by 2 × 10⁴ and dividing the result by thesurface area.

A preferred catalyst composition comprises a catalyst composite asdescribed above with the further limitation that the catalyst compositeshall have a maximum compacted density of 0.75 gram per cubic centimeterand shall have a pore volume of at least 0.60 cubic centimeter per gramas determined by the mercury test method previously described. Thecompacted density as employed in this application refers to the testmethod whereby four substantially equal portions of the catalyst areadded to a graduated cylinder with the side of the graduated cylindertapped after the addition of each portion until a final catalyst levelis obtained. After a measured volume, normally 200 ml of catalyst, isobtained in the graduated cylinder, the weight of the catalyst isdetermined and the final compacted density calculated by dividing thetotal catalyst weight with the volume of the catalyst in the graduatedcylinder.

In preparation of the hydrogenation catalyst compositions, an aluminasupport containing less than 2.0 weight percent impurities, such assilica, and having a bayerite content of 0 to 50 weight percent isemployed. Although not to be limited thereto, desirably the minimumparticle diameter of the alumina support material employed in formingthe catalyst composite falls within the range of 1/8 to 1/60 inch. Thepore volume of the alumina support should be at least 0.65 cc per gramas determined by nitrogen adsorption and the average pore radius shouldbe at least 32 A units. The pore size distribution of the aluminasupport should be such that at least 25 percent of the pore volume iscontained in pores having a radius in the range of 50 to 300 A units.

In the preparation of the low compacted density catalyst compositions ofthis invention, the pore volume of the alumina support should be atleast 0.65 cc per gram as determined by the nitrogen adsorption methodand should be at least 0.75 cc per gram as determined by the mercurytest method.

In preparation of the catalyst composite, the alumina support is driedto remove any free water therefrom. Typically, the alumina can be driedat a temperature of 250°F. (121°C.) for a time ranging from 4 to 24hours. Thereafter, the alumina is calcined at a temperature in the rangefrom 800° to 1600°F. (427° - 871°C.) in an oxygen-containing atmosphere,such as air, for a period ranging from 1 to 24 hours, prior toimpregnation of the alumina with the hydrogenation metals.

The preparation of the catalyst composite, as hereafter described, willbe especially suitable to nickel-tungsten-on-alumina catalyst compositesalthough it will be understood by those skilled in the art that thepreparation method described herein can also be adapted to other GroupVI-B and Group VIII hydrogenation metal catalysts.

The alumina support, such as extruded alumina pellets, pretreated by theprocedure described above, can be admixed with tungsten which is in theform of any water-soluble compound of tungsten, the tungsten beingpresent as the anion. Ammonium salts of tungstic acid and particularlyammonium metatungstate, ammonium tungstate or ammoniasilica-dodecatungstate can be employed in the impregnation procedure.The concentration of tungsten in the finished catalyst should be in therange of 5 - 25 percent by weight. The wet impregnated alumina is thenpreferably dried at, for example, a temperature of 250°F. (121°C.) for aperiod of time ranging from 4 up to 24 hours. Following drying, thealumina impregnated with the tungsten can be calcined.

Thereafter, the alumina support can be contacted with an aqueoussolution of a nickel salt such as the nitrate, sulfate, or chloride.Alternatively, salts of organic acids such as acetate, formate, orpropionate can be utilized. Sufficient salt is admixed with the aqueoussupport so as to provide a catalyst composite containing from 5 - 20percent by weight nickel. The wet catalyst composite can then be driedin a second drying step at a temperature of, for example, 250°F.(121°C.) for 24 hours. Following the drying step, the catalyst compositecan then be calcined at a temperature in the range of 800° to 1600°F.(427° - 871°C.) for a period of 1 to 24 hours.

Although a two-step impregnation catalyst preparation procedure has beendescribed, it is within the skill of the art, and the scope of thisinvention, to employ a single impregnation step in adding thehydrogenation metals to the alumina support. As previously noted whenthe use of the catalyst in sulfided form is desired, the catalyst can bepresulfided, after calcination, or after calcination and reduction.

The catalyst composite as prepared will have an average pore radius ofat least 40 A units, preferably from 45 to 75 A units. The radius of thepores comprising at least 40 percent, preferably at least 65 percent, ofthe nitrogen pore volume will be in the range from 50 to 300 A units.The pore volume of the catalyst composite will be at least 0.45 cc pergram, preferably at least 0.50 cc per gram, as determined by nitrogenadsorption. The surface area of the catalyst composite will be at least150 square meters per gram.

The low density catalyst composites of this invention will, in additionto the characteristics described in the above paragraph, have a porevolume of at least 0.60 cc per gram as determined by the mercury testmethod and will have a maximum compacted density of 0.75 gram per cc.

The hydrogenation reactions effected pursuant to the process of thisinvention can be conducted at a temperature in the range of 500° to800°F. (260° to 427°C.), preferably 550° to 750°F. (277° to 388°C.). Thehydrogenation process is conducted by contacting the catalyst compositewith the aromatic feed in the presence of uncombined hydrogen partialpressures in the range of 200 to 4000 psig (14.1 to 282.0 kilograms percm²). Hydrogen is circulated through the reactor at a rate between about700 and 15000 standard cubic feet (19.9 to 42.7 cubic meters) per barrelof feed with the hydrogen purity varying from 60 to about 100 percent.

After the hydrogen is recycled, it may be necessary to provide forbleeding off a portion of the recycled gas and to make up hydrogen inorder to maintain the hydrogen purity within the range specified. Ifdesired, the recycled gas can be washed with a chemical absorbent forhydrogen sulfide or otherwise treated in a conventional manner to reducethe hydrogen sulfide content thereof prior to recycling.

The hydrogenation reaction can be continuously conducted in the liquidor vapor phase and at a liquid weight hourly space velocity in the rangeof 0.25 to 10, preferably 0.5 to 3.0. Reaction zone pressures in therange of 200 to 5000 psig (14.1 to 353 kilograms per square centimeter),normally in the range of 750 to 2000 psig (52.7 to 140.5 kilograms persquare centimeter), are maintained in the hydrogenation zone.

The following examples are presented to demonstrate the objects andadvantages of the invention. It is not intended, however, to limit theinvention to the specific embodiments presented therein.

EXAMPLE 1

In this example a catalyst composite containing 6.0 weight percentnickel and 19.0 weight percent tungsten was prepared. A solution of80.55 grams of ammonium metatungstate (92.5 weight percent WO₃) in 309ml of distilled water was employed to impregnate 212.7 grams ofcommercial 1/16-inch (0.159 cm) calcined alumina extrudates driedovernight at a temperature of 700°F. (371°C.) prior to use. The aluminasupport had a compacted density of 0.411 grams per cc, a surface area of217.6 square meters per gram, a pore volume of 0.792 cc's per gram asdetermined by the nitrogen adsorption test method, and a pore radius of72.8 A units. The pore volume distribution of the alumina support was asshown below:

    Pore Volume Distribution                                                      % of Pore Vol. in Pores of                                                    ______________________________________                                        250-300      A radius 2.2                                                     200-250               5.2                                                     150-200               10.3                                                    100-150               24.0                                                     90-100               7.6                                                     80-90                 10.2                                                    70-80                 10.6                                                    60-70                 9.3                                                     50-60                 7.1                                                     45-50                 3.1                                                     40-45                 3.0                                                     35-40                 2.2                                                     30-35                 2.3                                                     25-30                 2.1                                                     20-25                 0.7                                                     15-20                 0.0                                                     10-15                 0.0                                                      7-10                 0.0                                                     ______________________________________                                    

The wet extrudates were oven dried overnight at 250°F. (121°C.) and thenimpregnated with a solution of 118.8 grams of nickel nitrate hexahydratein 266 ml distilled water. The wet extrudates were again oven driedovernight at 250°F. (121°C.) and calcined at 1000°F. (538°C.) by raisingthe temperature to 1000°F. (538°C.) in about 6 hours and holding at thattemperature for about 10 hours.

The prepared catalyst had a surface area of 162.6 square meters pergram, a pore volume of 0.511 cc/g as determined by nitrogen adsorption,a pore volume of 0.75 g/cc as determined by the mercury test method, acompacted density of 0.646 grams per cc, and a pore radius of 62.9 Aunits. The pore volume distribution as determined by nitrogen adsorptionis as shown below:

    Pore Volume Distribution                                                      % of Pore Vol. in Pores of                                                    ______________________________________                                        250-300      A radius 2.3                                                     200-250               5.1                                                     150-200               9.8                                                     100-150               21.8                                                     90-100               6.6                                                     80-90                 9.1                                                     70-80                 10.1                                                    60-70                 9.6                                                     50-60                 7.8                                                     45-50                 3.7                                                     40-45                 3.2                                                     35-40                 3.0                                                     30-35                 2.1                                                     25-30                 2.7                                                     20-25                 2.3                                                     15-20                 0.9                                                     10-15                 0.0                                                      7-10                 0.0                                                     ______________________________________                                    

EXAMPLE 2

In this example a catalyst composite containing 12.5 weight percentnickel and 12.5 weight percent tungsten was prepared. A solution of 52.3grams of ammonium metatungstate dissolved in 305 ml of distilled waterwas used to impregnate 209.6 grams of the commercial calcined 1/16 inch(0.159 cm) alumina extrudates of Example 1 dried overnight at 700°F.(371°C.) prior to use. The wet extrudates were dried overnight at 250°F.(121°C.) and impregnated with a solution of 244.2 grams of nickelnitrate hexahydrate dissolved in 270 ml of distilled water. The wetextrudates were then oven dried overnight and calcined by raising thetemperature to 1000°F. (538°C.) in about 6 hours and holding theextrudates at that temperature for 10 hours.

The prepared catalyst had a surface area of 172.6 square meters pergram, a pore volume of 0.517 cc per gram as determined by nitrogenadsorption, a pore volume of 0.745 cc per gram as determined by themercury test method, a compacted density of 0.660 gram per cc, and apore radius of 59.9 A units. The pore volume distribution as determinedby nitrogen adsorption is as shown below:

    Pore Volume Distribution                                                      % of Pore Vol. in Pores of                                                    ______________________________________                                        250-300      A radius 2.3                                                     200-250               4.8                                                     150-200               9.0                                                     100-150               21.3                                                     90-100               6.4                                                     80-90                 8.7                                                     70-80                 8.5                                                     60-70                 8.5                                                     50-60                 9.5                                                     45-50                 3.5                                                     40-45                 3.4                                                     35-40                 3.3                                                     30-35                 2.5                                                     25-30                 3.1                                                     20-25                 2.7                                                     15-20                 2.5                                                     10-15                 0.0                                                      7-10                 0.0                                                     ______________________________________                                    

EXAMPLE 3

The catalyst preparation procedure of Example 1 was repeated with theexception that the procedure was adapted to produce catalyst compositescontaining varying amounts of nickel and tungsten. The concentrations ofmetals on the alumina support and the characteristics of the preparedcatalyst composites (hereinafter referred to as Catalyst A, B and C) areas set forth below:

                    Catalyst                                                                             Catalyst Catalyst                                                      A      B        C                                             ______________________________________                                        Concentration of                                                               nickel, Wt. % of                                                              cat. composite   8.0      5.0      9.0                                       Concentration of                                                               tungsten, Wt. % of                                                            cat. composite   8.0      5.0      16.0                                      Surface area, sq.                                                              meters per gram  184.6    199.9    166.0                                     Pore volume(nitrogen                                                           adsorption),cc's/g                                                                             0.624    0.678    0.527                                     Pore radius, A units                                                                            67.7     67.9     63.5                                      Pore volume distri-                                                            bution                                                                       % of Pore vol. in                                                             Pores of                                                                      250-300      A radius 2.4      2.5    2.3                                     200-250               5.7      5.1    4.7                                     150-200               10.1     10.2   10.2                                    100-150               22.9     23.8   22.0                                     90-100               4.8      7.0    6.8                                     80-90                 11.5     9.6    9.1                                     70-80                 9.6      10.2   9.4                                     60-70                 9.8      9.2    9.1                                     50-60                 7.3      7.0    7.3                                     45-50                 3.7      3.6    3.8                                     40-45                 2.9      2.7    3.2                                     35-40                 2.9      2.9    3.2                                     30-35                 2.2      1.9    2.5                                     25-30                 2.2      2.3    2.8                                     20-25                 2.2      2.1    2.9                                     15-20                 0.0      0.0    0.5                                     10-15                 0.0      0.0    0.0                                      7-10                 0.0      0.0    0.0                                     Compacted density, g/cc                                                                         .587     .512     .649                                      ______________________________________                                    

EXAMPLE 4

The catalyst preparation method of Example 3 (Catalyst A) was repeatedwith the exception that a single impregnation step was employed in theaddition of the nickel and tungsten to an alumina support having thefollowing properties:

    Surface area, sq.                                                              meters per gram    206                                                       Compacted density, g/cc                                                                           0.49                                                      Pore volume (nitrogen                                                          adsorption), cc's/g                                                                              0.89                                                      Pore volume (ml/g) in pores                                                    less than                                                                    120           A diameter                                                                              0.45                                                  200                     0.83                                                  350                     0.86                                                  700                     0.87                                                  1,000                   0.88                                                  10,000                  0.89                                                  152,000                 0.89                                                  Mercury Density     0.84                                                  

The properties of the catalyst composite was as shown below:

    Surface area, sq.                                                              meters per gram    194.6                                                     Compacted density, g/cc                                                                           .561                                                      Pore volume (nitrogen                                                          adsorption), cc's/g                                                                              0.470                                                     Pore radius, A units                                                                              48.4                                                      Pore volume distribution                                                      % of Pore vol. in Pores of                                                    250-300      A radius   0.5                                                   200-250                 0.9                                                   150-200                 1.6                                                   100-150                 5.1                                                    90-100                 10.9                                                  80-90                   13.3                                                  70-80                   14.0                                                  60-70                   13.6                                                  50-60                   11.7                                                  45-50                   4.8                                                   40-45                   4.8                                                   35-40                   4.7                                                   30-35                   3.1                                                   25-30                   3.9                                                   20-25                   3.8                                                   15-20                   3.4                                                   10-15                   0.0                                                    7-10                   0.0                                               

EXAMPLE 5

In this example the catalyst composite of Example 1 was employed tohydrogenate a feed comprised of 29.5 volume percent saturatedhydrocarbons, 4.5 volume percent olefins, 66.0 volume percent aromatics,and further characterized as follows:

    Gravity, API       26.2                                                       Sulfur, Wt. %      0.62                                                       Nitrogen, (ppm)    260                                                        Distillation, ASTM, °C.                                                  10%              218°C.                                                50%              260°C.                                                90%              312°C.                                          

The hydrocarbon feed was continuously charged to the reactor containingthe catalyst composite at a space velocity of 1.0 volume of feed perhour per volume of catalyst. A pressure of 105.6 kilograms per squarecentimeter was maintained in the hydrogenation zone. Hydrogen gas of 75volume percent purity was passed at the rate of 284 cubic meters perbarrel of hydrocarbon feed to the hydrogenation zone. Two hydrogenationruns were conducted under the stated conditions with an operatingtemperature in the first run of 360°C. and the second run conducted at areaction temperature of 371°C..

The product recovered from the hydrogenation zone was analyzed foraromatic concentration with the results shown below:

                      Vol. %                                                                        Aromatics                                                   ______________________________________                                        Operating temp. of 360° C.                                                                 37.5                                                      Operating temp. of 371° C.                                                                 36                                                        ______________________________________                                    

From the above it can be seen that 43.2 and 45.4 percent, respectively,of the aromatics in the feed to the hydrogenation zone werehydrogenated.

EXAMPLE 6

In this example the runs of Example 5 were repeated with the exceptionthat the 0.159 centimeter diameter catalyst particles comprising 6.0weight percent nickel, 19.0 weight percent tungsten and alumina had thefollowing properties:

    Surface area, sq.                                                              meters per gram    209.3                                                     Compacted density, g/cc                                                                           0.826                                                     Pore volume (nitrogen)                                                         adsorption), cc's/g                                                                              0.496                                                     Pore radius, A units                                                                              60.7                                                      Pore volume distribution                                                      % of Pore vol. in                                                             Pores of                                                                      250-300      A radius   1.3                                                   200-250                 2.4                                                   150-200                 4.0                                                   100-150                 10.8                                                   90-100                 5.0                                                   80-90                   7.9                                                   70-80                   9.1                                                   60-70                   10.4                                                  50-60                   11.0                                                  45-50                   6.1                                                   40-45                   6.3                                                   35-40                   6.2                                                   30-35                   5.7                                                   25-30                   5.7                                                   20-25                   5.2                                                   15-20                   3.1                                                   10-15                   0.0                                                    7-10                   0.0                                                   Pore volume (mercury test                                                      method, cc/g       .53                                                   

The product recovered from the hydrogenation zone was analyzed foraromatics concentrations, with the results shown below:

                      Vol. %                                                                        Aromatics                                                   ______________________________________                                        Operating temp. of 360° C.                                                                 37.5                                                      Operating temp. of 371° C.                                                                 35.5                                                      ______________________________________                                    

A comparison of the results obtained from this example with the resultsobtained in Example 5 demonstrates that a catalyst composite having asubstantially lower compacted density (0.646 vs. 0.826) is substantiallyequally effective in the hydrogenation of aromatic hydrocarbons. Thus,it is evident that substantial economic advantage would result fromemploying the catalyst composite of Example 1 in commercial aromatichydrogenation processes in that the cost for each reactor fill would besubstantially lower.

EXAMPLE 7

In this example a catalyst composite prepared by employing a singleimpregnation step was employed in the hydrogenation of an aromatic feed.The catalyst composite comprising 6 weight percent nickel, 19 weightpercent tungsten and alumina had the following properties:

    Surface area, sq.                                                              meters per gram    166                                                       Compacted density, g/cc                                                                           .682                                                      Pore volume (nitrogen                                                          adsorption), cc's/g                                                                              .51                                                       Pore volume (mercury                                                           test method, cc's/g                                                                              .58                                                       Pore volume distribution                                                      % of Pore vol. in                                                             Pores of                                                                      250-300      A radius   2.7                                                   200-250                 5.0                                                   150-200                 13.2                                                  100-150                 24.6                                                   90-100                 6.1                                                   80-90                   7.3                                                   70-80                   7.2                                                   60-70                   7.6                                                   50-60                   6.4                                                   45-50                   3.3                                                   40-45                   3.0                                                   35-40                   3.5                                                   30-35                   2.0                                                   25-30                   3.3                                                   20-25                   2.9                                                   15-20                   1.9                                                   10-15                   0.0                                                    7-10                   0.0                                                   Pore radius, A units                                                                              61.3                                                  

A hydrocarbon feed comprising 75.5 volume percent aromatics, 6.0 volumepercent olefins and 18.5 volume percent saturated hydrocarbons wascontinuously charged to a hydrogenation reactor containing the aboveidentified catalyst composite having an average particle diameter sizeof 0.15 centimeter. A space velocity of 1.0 volume of feed per hour pervolume of catalyst was maintained during the run. The pressure withinthe hydrogenation zone was 105.6 kilograms per square meter and hydrogengas of 75 volume percent purity was passed to the hydrogenation zone atthe rate of 284 cubic meters per barrel of hydrocarbon feed. Threehydrogenation runs were conducted under the stated conditions with theoperating temperatures in the runs comprising 343°C., 360°C. and 377°C.respectively.

For each run the product recovered from the hydrogenation zone wasanalyzed for aromatics concentration with the results shown below:

                      Vol. %                                                                        Aromatics                                                   ______________________________________                                        Operating temp. of 343° C.                                                                 52.5                                                      Operating temp. of 360° C.                                                                 48.5                                                      Operating temp. of 377° C.                                                                 48.0                                                      ______________________________________                                        039520690190x n

EXAMPLE 8

In this example a catalyst composite comprising 6.0 weight percentnickel, 19.0 weight percent tungsten and alumina was employed in thehydrogenation of the hydrocarbon feed of Example 5. The catalystcomposite with an average particle diameter of 0.15 centimeter had thefollowing properties:

    Surface area, sq.                                                              meters per gram    158.3                                                     Compacted density, g/cc                                                                           0.947                                                     Pore volume (nitrogen                                                          adsorption), cc's/g                                                                              .323                                                      Pore volume (mercury                                                           test method), cc/g .35                                                       Pore radius, A units                                                                              40.9                                                      Pore volume distribution                                                      % of Pore vol. in                                                             Pores of                                                                      250-300      A radius   2.1                                                   200-250                 2.3                                                   150-200                 3.5                                                   100-150                 7.2                                                    90-100                 3.9                                                   80-90                   5.8                                                   70-80                   7.3                                                   60-70                   9.6                                                   50-60                   10.6                                                  45-50                   6.8                                                   40-45                   6.7                                                   35-40                   7.5                                                   30-35                   6.1                                                   25-30                   7.6                                                   20-25                   6.1                                                   15-20                   6.7                                                   10-15                   0.2                                                    7-10                   0.0                                               

Comparing the catalyst composite of this example with the catalystcomposite of Example 1, it can be seen that the catalyst composite ofthis example has a substantially higher compacted density (0.947 vs.0.646 g's/cc), a substantially lower pore radius (40.9 vs. 62.9 Aunits), and a substantially lower pore volume as determined by both thenitrogen and mercury test methods (0.323 vs. 0.511 and 0.35 vs. 0.75g/cc, respectively). The effect of these distinguishing catalystcharacteristics in the hydrogenation of aromatic hydrocarbons wasdemonstrated by conducting runs under the conditions, includingoperating temperatures, of Example 5.

For each of the 2 runs the aromatics concentration of the product wasdetermined with the results shown below:

                      Vol. %                                                                        Aromatics                                                   ______________________________________                                        Operating temp. of 360° C.                                                                 43.0                                                      Operating temp. of 371° C.                                                                 40.5                                                      ______________________________________                                    

From the above it can be seen that 34.9 and 38.6 percent respectively ofthe aromatics in the feed to the hydrogenation zone were hydrogenated. Acomparison of the results obtained in this example and Example 5demonstrates the substantial improvement in aromatic hydrogenationactivity as a result of employing the novel catalyst composition of thisinvention.

Although the invention has been described with reference to specificembodiments, references, and details, various modifications and changeswill be apparent to one skilled in the art and are contemplated to beembraced in this invention.

We claim:
 1. A process for catalytically hydrogenating an aromatic feedwhich comprises contacting said aromatic feed with hydrogen athydrogenation conditions in the presence of a catalyst comprising ahydrogenating component selected from the Group VI-B metals and a secondhydrogenating component selected from the Group VIII metals compositedwith an alumina base, at least 40 percent of the volume of pores of thecatalyst composite being in pores having a radius in the range of 50 to300 A units, the average pore radius of said catalyst composite being atleast 40 A units as determined by nitrogen adsorption, the surface areaof said catalyst composite being at least 150 square meters per gram,and the pore volume of said catalyst composite being at least 0.45 cubiccentimeter per gram as determined by nitrogen adsorption, said catalystcomposite having been prepared by calcining an alumina support having abayerite content in the range of 0 to 50 weight percent at a temperaturein the range of 427° - 871°C., admixing said alumina support with thetwo hydrogenating components, and thereafter calcining the catalystcomposite at a temperature in the range of 427° - 871°C.
 2. The processof claim 1 wherein said catalyst composite comprises from 5 to 25percent by weight of a Group VI-B metal, from 5 to 20 percent by weightof a Group VIII metal and alumina.
 3. The process of claim 2 wherein thehydrogenation process is conducted at a temperature in the range of 260°to 427°C., at a liquid weight hourly space velocity in the range of 0.25to 10, at a pressure in the range of 352 kilograms per square centimeterand in the presence of hydrogen partial pressures of 14.1 to 282kilograms per square centimeter.
 4. The process of claim 3 wherein saidcatalyst composite shall have a pore volume of at least 0.60 cc/g asdetermined by mercury test method, and a maximum compacted density of0.75 gram per cc.
 5. The process of claim 4 wherein the Group VI-B metalis tungsten and the Group VIII metal is nickel.
 6. The process of claim3 wherein the Group VI-B metal is tungsten and the Group VIII metal isnickel.